Commemorative signs pertaining to the history of the Lithuanian parliamentary tradition can be found in the Grand Courtyard of Building 1 of the Seimas.

It is here that oak trees were planted on 15 May 2000, on the occasion of the 80th anniversary of the Constituent Seimas, and on 1 May 2004, to mark Lithuania’s accession to the European Union. A silver fir tree was planted on 13 January 2001, on the Day of the Defenders of the Freedom of Lithuania.

On 7 July 2020, a capsule of the Office of the Seimas of the Republic of Lithuania was buried to commemorate the centenary of the launch of the Office of the Seimas of the Republic of Lithuania.